Selenium rectifier



y 1960 w. J. COYLE 2,935,665

SELENIUM RECTIFIER Filed Sept. 8, 1958 United States Patent SELENIUMRECTIFIER William J. Coyle, Waltham, Mass, assignor to United- CarrFastener Corporation, Cambridge, Mass, a corporation of DelawareApplication September 8, 1958, Serial No. 759,692

3 Claims. (Cl. 317-234) My invention relates to electrical rectifierassemblies and particularly to rectifiers employing asymmetric units ofan imperfect conductor.

In rectifiers of this type, pressure of the conductors on the imperfectconductors must be kept at a constant amount. If the pressure exerted onthe semi-conductors is increased there is a tendency for an increase totake place in the reverse current of the rectifier lowering itsefficiency.

The primary object of this invention is to provide a resilient lead-inconductor which would exert at all times an even, unvarying pressure onthe imperfect conductors.

Another object of the invention is to provide a spring like conductorwhich can not be loosened under normal operating conditions.

Other objects of this invention will, in part, be obvious, and will, inpart, appear hereinafter.

In the drawing:

Fig. 1 is a perspective view of the rectifier assembly;

Fig. 2 is a section taken on line 2-2 of Fig. 1;

Fig. 3 is a section taken on line 33 of Fig. 2;

Fig. 4 is a section taken on line 4-4 of Fig. 1; and

Fig. 5 is a plan view of the cap.

Referring now to the drawings, the improved rectifier assembly comprisesan insulating rectilinear housing 12, three terminals consisting of twocathode leads 14 and an anode lead 16, a resilient spring conductor orcontact 18, a plate or cap 20, and a semiconductor (rectifying cell) 22.

The housing 12 comprises a rectangular base 24 having two circularrecessses 26 with a recess aperture 28 formed axially in the bottom ofthe recess 26 through the base 24. A third aperture 30 is formed throughthe base 24 midway between the recesses 26 without being recessed.Integral with and at right angles to the edges of the base 24, there aretwo side walls 32 and two end walls 34 forming a box with the base 24. Ashoulder 36 is formed in each of the end walls 34 as illustrated in Fig.3.

The resilient spring conductor 18 comprises a comparatively longrectangular piece of conductive material, such as copper, whose terminalends 38 are bent back upon themselves to form an elbow 40 and twoconverging legs 41. A conductor aperture 42 is formed in the conductor18 midway between the two elbows 40 so that the conductor aperture 42will be superimposed upon that lead-in aperture 30 when the conductor 18is placed on the base 24. The three pig tails or leads numbered 14 and16 are all constructed of conductive material and comprise a long, thincylindrical tail 44 integrally capped by a comparatively fiat circularhead 46. A semi-conductor 22 is affixed to the head 46 of the cathodeleads 14. In the preferred embodiment a selenium cell is used, however,any other semi-conductor such as germanium will work.

The cap is a rectangular piece of non-conductive material formed to reston the shoulders 36 and whose 'ice edges will bear against the walls 32and 34 when engaged with the housing 12. Any type of non-conductivematerial may be used, however, in the preferred embodiment plastic wasused.

To assemble the device 10, the tails 44 of the cathode leads 14, withtheir semi-conductors 22 attached, are passed through the apertures 28.The tails 44 are of sufficient length to extend a few inches beyond thebase 24 after being forced through the apertures 28. The heads 46 bearagainst the bottom of the recesses 26 and the semi-conductors 22 extenda slight distance above the face 48 of the base 24. The tail 44 of theanode 16 is passed through the conductor aperture 42 so that the head 46bears against the upper surface of the conductor 18. The head 46 of theanode lead 16 is then afiixed to the conductor 18 by any of the numerousmeans available. In the preferred embodiment the said head and conductorare soldered together. For example, the head 46 may be formed to clipinto the conductor 18. The tail 44 of the anode 16 is then passedthrough the aperture 38 until the conductor 18 bears against thesemiconductors 22. At this juncture, the terminal ends 38 of theconductor 18 extend slightly above the line of the shoulders 36. The cap20 is placed on top of the terminal ends 38 of the conductor 18 forcingthe legs 41 toward each other until the cap rests on the shoulders 36.When the cap 20 is engaged as set forth above, the conductor 18 isfirmly pressed against the semi-conductors 22 forming a good electricalconnection. The area between the walls 32 and 34 over the cap 20 isfilled with potting compound 50 to hold the cap in place and seal theelectrical connectors from outside dirt and moisture. Of course, theexternal dimensions of the housing 12 may be varied to suit difierentapplications. The assembly will also work efficiently if only onecathode lead is used, since the axial force is equal along the contactpoints between the conductor and any number of semiconductors.

Since certain other obvious modifications may be made in this devicewithout departing from the scope of the invention, it is intended thatall matters contained herein be interpreted in an illustrative and notin a limiting sense.

I claim:

1. An encapsulated rectifier assembly comprising terminal leads, ahousing of non-conductive material, aresilient spring conductor in saidhousing having its terminal ends bent back upon themselves to form twoelbows, an imperfect conductor in said housing of the class describedhaving one portion sprayed with a metallic layer, and a means oftransmitting electrical current to said spring conductor, a 'cap holdingsaid conductor in assembly with said housing, said spring conductorexerting horizontal pressure on said imperfect conductor when said capis placed in said housing.

2. An encapsulated rectifier assembly comprising a housing ofnon-conductive material having a cap, a rectifying cell of the classdescribed, a resilient spring conductor having its terminal ends bentback upon themselves to form two U-shaped elbows, and a means oftransmitting electrical current to said spring conductor, said springconductor kept in contact with said rectifying cell through mechanicaloperation of the cap and the said terminal ends of the spring conductor.

3. An encapsulated semi-conductor rectifying assembly comprising ahousing of non-conductive material, a resilient spring conductor in saidhousing having its terminal ends bent back upon themselves to form twoelbows, three terminal leads, said leads consisting of an anode leadattached to said spring conductor between said elbows and two separatecathode leads, an imperfect 2,93 5,665 3 4 Gpnductor in said housing ofthe class described having References Cited in the file 'of this patentone portion sprayed with a metallic layer, a cap holding UNITED STATESPATENTS said conductor in assembly with said housing, said springconductor exerting horizontal pressure on said imperfect 2707252 Peteret 1955 conductor when said cap is placed in assembly with said 52'853662 Woods Sept 1958 housing. 2,879,453 hu ert Mar. 24, 1959 UNITEDSTATES PATENT OFFICE CERTlFlCA'lE 0F CORRECION Patent No 2335,665 May3', 1960 William J Coyle Q e printed specification It is herebycertified that error appears in th t requiring correction and that thesaid Letters of the above numbered paten Patent should readas correctedbelow.

line 63 for "operation day of October 1960,

Column 2 read cooperation Signed and sealed this 25th (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents AttestingOflicer

1. AN ENCAPSULATED RECITIFIER ASSEMBLY COMPRISING TERMINAL LEADS, AHOUSING OF NON-CONDUCTIVE MATERIAL, A RESILIENT SPRING CONDUCTOR IN SAIDHOUSING HAVING ITS TERMINAL ENDS BENT BACK UPON THEMSELVES TO FORM TWOELBOWS, AN IMPERFECT CONDUCTOR IN SAID HOUSING OF THE CLASS DESCRIBEDHAVING ONE PORTION SPRAYED WITH A METALLIC LAYER, AND A MEANS OFTRANSMITTING ELECTRICAL CURRENT TO SAID SPRING CONDUCTOR, A CAP HOLDINGSAID CONDUCTOR IN ASSEMBLY WITH SAID HOUSING, SAID SPRING CONDUCTOREXERTING HORIZONTAL PRESSURE ON SAID IMPERFECT CONDUCTOR WHEN SAID CAPIS PLACED IN SAID HOUSING.